1. Field of the Invention
The present invention relates to a substrate transporting device.
2. Prior Art
Conventionally, the following two types of devices are known for transporting substrates used in manufacturing, for instance, semiconductor chips.
In the first type, feeding claws or feeding pins perform a rectangular motion within a vertical plane (known as a tact operation) and push the rear ends of the substrates (or the feeding pins are inserted into holes of the substrates), so that the substrates are fed one pitch at a time by the feeding claws or feeding pins. In this type, the feeding claws or feeding pins extend downward from above or extend upward from below. Japanese Patent Application Laid-Open (Kokai) Nos. S55-11345 and S55-88351 are, respectively, examples that teach this type of device.
The second type of device includes upper and lower claws that make a rectangular motion in a vertical plane. In this device, the substrates are held from above and below by the upper and lower claws and fed one pitch at a time. Japanese Patent Application Publication (Kokoku) Nos. S63-56121 and H6-80691, for example, disclose this type of device.
In devices of the first type that include the feeding claws or feeding pins extending downward from above, the window damper which presses the substrates against the beating block interferes with the movement of the feeding claws or the feeding pins. Accordingly, so as to solve this problem, the window damper is split so as to form a passage which the feeding claws or feeding pins pass through. However, when the window damper is split, the strength of the window damper decreases greatly, and the substrates are not held firmly. Furthermore, the portion of the split window damper that forms a passage for the feeding claws or feeding pins cannot firmly hold the substrates; accordingly, when bonding points are located in this area, the bonding quality drops. So as to overcome these problems and perform good bonding stably, it is necessary to re-position the feeding claws or feeding pins to positions which avoid the bonding points on the substrates; and it is also necessary to change or replace the window damper to one that matches the re-positioning.
Furthermore, in a wire bonding apparatus, a bonding tool through which the wire passes and an electric torch electrode which forms a ball on the tip end of the wire, etc., are provided at the tip end of a bonding arm that is installed on the bonding head; and the attachment positions of these parts are set as low as possible (i. e., as close to the substrate as possible) so as to avoid the bonding speed from decreasing. Accordingly, the feeding claws or feeding pins must feed the substrates after the bonding head has been withdrawn to a predetermined location so that the feeding claws or feeding pins do not contact the bonding tool or electric torch electrode, etc. when the substrates are fed by the feeding claws or feeding pins.
In devices of the above-descried first type that include the feeding claws or feeding pins extending upward from below and feeds the substrates by pushing substantially the central portions of the substrates, it is necessary to form a passage for the feeding claws or feeding pins by splitting the heating block. Furthermore, when the feeding claws or feeding pins are installed on the substrate guide rail side, the width of the heating block must be reduced by a corresponding amount.
Accordingly, in these types of devices, when the positions of the feeding claws or feeding pins are to be altered, the relationship with the heating block prevents a simple positional alteration. Furthermore, if the heating block is not installed on the undersides of the substrates in the positions of the bonding points on the substrates, the substrates are not heated, and favorable bonding cannot be performed. Accordingly, the feeding claws or feeding pins must be installed in positions which can avoid the bonding points on the substrates. It is, therefore, necessary to change the positions of the feeding claws or feeding pins in each case according to the substrates to be handled. It is further necessary to change the heating block to one that conforms to these positions. In addition, since the feeding claws or feeding pins are hidden beneath the substrates, maintenance work is difficult.
In devices of the second type, since the substrates are held by feeding claws (upper and lower claws), bonding cannot be performed in the area held by the feeding claws or the area near the area held by the feeding claws. Furthermore, in the case of a window clamper that has a broader bonding area, there is considerable interference between the window clamper and the feeding claws. In addition, since the space through which the lower claws pass must be installed on the substrate guide rail side, the width of the heating block is reduced by a corresponding amount. Moreover, since the substrates which are heated are held by the feeding claws, the heat of the substrates escapes through the feeding claws.